Life on our planet exists because of water, and yet despite how fundamental it is, water is something we take completely for granted — (much like breathing).
We know we need to drink water to stay alive and we have some vague idea of the good it does for us, but beyond that we know almost nothing about this life-giving substance.
Before we get into the practical health stuff — why clean water is so critical for your health, why tap water isn't actually clean, and how to properly purify it — we need to clear up one big misconception first.
Quick technical detour.
In school you were taught that water is H2O, but that's not quite true.
Unless we're being extremely hand-wavy about it, a single H2O molecule doesn't have any of the observable properties we associate with water.
If we imagine a glass of water that's as pure as theoretically possible, its chemical makeup would be something like H2O, OH-, H3O+. In reality it would also contain a bunch of bound and less common ions. But even that explanation is an oversimplification, because we can't actually get water that pure anywhere.
The H2O idea is based on the fact that if you look at what water is made of, you can observe hydrogen and oxygen atoms in roughly a 2:1 ratio.
In reality it's way more complicated than that. Because that H2O could just as well be D2O or even HDO. These are fundamentally the same molecule — made from the same elements, but from different isotopes.
If the property of water we're measuring is solubility, then yes, they're identical molecules. But if we want to measure something like boiling point, then comparing the atomic masses of hydrogen and deuterium makes it obvious we're dealing with two very different substances.
So what does all this mean?
It means water is not just water. Water fills a much more complex, interesting, powerful & important biological role than it appears to at first glance.
I opened this topic so I can refer back to it in future articles when we talk about hydrogen-enriched water, deuterium-depleted water, or EZ water (the fourth phase of water).
The human body is 60-75% water by volume.
Even more striking — because water molecules are so small, if you counted every single molecule in your body, 99% of them would be hydrogen molecules.
With those facts in mind, it's easy to see why drinking clean water matters so much for our health and overall wellbeing. And yet it seems like in the Western world, people just can't connect their health problems to the quality of the water they're drinking.
We simply trust that the water coming out of our tap is clean and that it can't harm our health.
The reality is that tap water quality standards and oversight are far from ideal. Tap water is not as clean and safe as it's made out to be. The standards define an acceptable amount of contaminants, but just because regulations accept a certain level of contaminants in your drinking water doesn't mean those contaminants aren't affecting your health. Often the tap water doesn't even meet those standards.
There's a common misconception that because the government is responsible for tap water, it must be clean enough to drink — it's not.
Of all municipally treated water, only 1% is actually consumed for drinking or cooking. The remaining 99% goes to toilets, washing machines, showers, baths, faucets & leaks. So it doesn't make economic sense to filter all of that water to a high enough standard. That's why the most practical approach is to purify your drinking water at the point of use.
For example, one water treatment dilemma that's relevant for people in Tallinn is chlorine. On one hand, adding chlorine to drinking water protects us from various pathogens lurking in water systems. On the other hand, chlorine use comes with disinfection byproducts that cause cancer and other health issues.
Reducing disinfectants could lead to more waterborne diseases, but adding new treatment processes drives the cost of water up significantly. History has shown that standards don't improve until society demands it.
But the amount of contaminants set by regulations is small and can't be harmful, right?
One glass of water won't do you much harm — depending on the contaminant, of course.
And while each glass contains only a small amount of contamination that your immune system can handle just fine, how many glasses do you drink in a week, a month, a year? It's a constant flow of health-damaging contaminants into your body.
Headaches, colds, stomach bugs — these can all be related to drinking unclean water.
But those are the acute issues. The real problem is the long-term accumulation of toxins and the deeper systemic damage they cause.
As I've mentioned in previous articles, we're constantly exposed to all kinds of environmental toxins. Those same toxins are in your drinking water too. The most common ones are arsenic, chlorine, chloroform, fluoride, lead, chromium-6 & perchlorate.
There are also plenty of other substances like pesticides, fungicides & herbicides (e.g. glyphosate), prescription drugs (e.g. birth control pills) & chemical industry residues that are designed to affect organisms even in incredibly tiny amounts. Meaning it doesn't take much to cause harm.
There are also contaminants your immune system simply can't fight: various chemicals, microplastics & lead (according to the World Health Organization (WHO), there is no safe level of lead exposure).
[2026 update: Two major contaminant categories have become much more prominent since this article was written:
PFAS ("forever chemicals"): In 2024, the US EPA set the first-ever legal limits for PFAS in drinking water (4 parts per trillion for PFOA and PFOS). PFAS are linked to cancer, immune system effects, and hormonal disruption. They are now considered one of the most significant drinking water contaminants worldwide. Reverse osmosis systems are effective at removing PFAS.
Microplastics: Research now shows individuals ingest tens of thousands of microplastic particles annually, with bottled water containing far more than tap water. Microplastics have been linked to inflammation, hormonal disruption, and organ accumulation. No country has yet set regulatory limits. Reverse osmosis systems can remove microplastics effectively.]
Longer-term symptoms can include high blood pressure, various organ damage & a weakened immune system. I want to stress here that there's no single factor that makes us sick or ages us faster. Aging is cumulative damage caused by small environmental and lifestyle insults to our bodies.
To get a sense of the health-damaging substances present in our everyday environment, I highly recommend reading Anthony G. Jay's "Estrogeneration: How Estrogenics Are Making You Fat, Sick, and Infertile".
Chronic ongoing exposure to various contaminants damages our DNA. This kind of damage isn't immediately noticeable — it only shows up decades later. Ever wondered why some old people are energetic and in great health while their peers can barely make it up the stairs? One of the factors is probably the damage accumulated over a lifetime. The less you damage your body, the healthier you age.
In other words, the longer you get to enjoy the healthy, energetic period of your life. The whole point of following a healthy lifestyle is to cause yourself as little damage as possible and let your body cope with the (unavoidable) damage it picks up just from living a normal life.
The good news is you don't have to wait long to notice the benefits of drinking clean water. This isn't some slow burn. Well-known American water expert and researcher Dr. Gerald Pollack has repeatedly pointed out that patients' health improves after switching from low-quality drinking water — which I've experienced myself. The most notable changes are improved cognitive and physical performance and fewer headaches.
Water purification technologies have a long and fascinating history — some more effective than others. You can read a comparison of the most common methods here.
Right now, reverse osmosis is the best and also the most widely used drinking water purification technology. Reverse osmosis is a multi-stage process that can remove 99% of all excess health-damaging substances from water.
Despite being very effective, reverse osmosis systems are expensive to install and maintain. They waste a lot of water during the purification process (for every liter of clean water produced, an additional 1-3 liters of water are used) and if they're not professionally maintained every six months, they can actually start producing toxic water.
Because traditional under-sink reverse osmosis systems can never fully drain due to their design, bacteria start thriving in the filtered water tank. And even if you do order professional maintenance, there's a risk it won't be done properly (the tank isn't sterilized correctly), which means the technology that's supposed to protect your health could end up damaging it instead.
Filter pitchers aren't a good solution either, simply because they're not built to remove the main toxins from your drinking water. They can reduce a few individual contaminants and give the water a better taste, but that's about where their effectiveness ends.
UV light water sterilization is gaining popularity, but it can't remove dissolved solids from water. And while UV kills pathogens, it can't remove the dead bacteria residue from the water.
Distillation is effective at removing microbes and dissolved solids, but struggles with chemicals that have a similar boiling temperature to water. The entire distillation process is also time-consuming and energy-intensive, and distillation machines are difficult to maintain and clean.
Since I was aware of the downsides of reverse osmosis systems and didn't want to renovate my kitchen, I found that this countertop reverse osmosis unit was the best solution for me. All in all, it was way more affordable, more convenient to use, and doesn't have the problems associated with under-sink reverse osmosis systems.
Those interested can also get a €25 discount with the coupon code puhasvesi25. [2026 update: This coupon code may have expired. Check tsirkaadia.ee for current pricing and products.]
We need clean water to be healthy and for our bodies to function properly. I encourage everyone to keep researching (drinking) water topics on their own!
Coming up soon are more water-related articles, where we'll go... Deeper.
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